Method and system of optimized volumetric imaging

ABSTRACT

A system of performing a volumetric scan. The system comprises a surface of positioning a patient in a space parallel thereto, a plurality of extendable detector arms each the detector arm having a detection unit having at least one radiation detector, and an actuator which moves the detection unit along a linear path, and a gantry which supports the plurality of extendable detector arms around the surface so that each the linear path of each respective the extendable detector arm being directed toward the space.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/726,316 filed on Dec. 24, 2012, which is a continuation of U.S.patent application Ser. No. 12/792,856 filed on Jun. 3, 2010, now U.S.Pat. No. 8,338,788, which claims the benefit of priority under 35 USC119(e) from U.S. Provisional Patent Application No. 61/229,549 filed onJul. 29, 2009.

U.S. patent application Ser. No. 13/726,316 incorporates by referenceU.S. Provisional Patent Application No. 61/229,549 filed on Jul. 29,2009, International Patent Application No. PCT/IL2005/001173 filed onNov. 9, 2005 (PCT Publication No. WO2006/051531 published May 18, 2006)and International Patent Application No. PCT/IL2006/000834 filed on Jul.19, 2006 (PCT Publication No. WO2007/010534 published Jan. 25, 2007).

The contents of the above applications are incorporated herein byreference in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to methodand system of imaging and, more particularly, but not exclusively, tomethod and system of medical imaging.

Volumetric scans such as CAT scans, PET scans, CT scans, MRI scans,Ultrasound scans, Laser 3D scanners, and the like are commonly used,particularly in the medical industry, to observe objects within astructure that would otherwise be unobservable. These scans have greatlyadvanced the capability of professionals such as doctors. Conventionalvolumetric scan is intended to produce a volumetric image of a largevolume of the body at high resolution. The ability to perform avolumetric scan with high resolution requires a large number ofdetectors, a fine motion control, and abundant processing resources forallowing the acquisition of a high resolution volumetric image in areasonable time. Furthermore, as the volumetric scan images a relativelylarge area, such as the torso, the patient radiation dose is relativelyhigh, for example when the volumetric scan is a CT scan.

Usually, volumetric imaging of a body structure is a multi-stageprocess. First biochemical, radioactive and/or contrast agents may beadministered. Then, measurements are taken at a set of predeterminedviews at predetermined locations, orientations, and durations. Then, thedata is analyzed to reconstruct a volumetric image of the body structureand an image of the body structure is formed. The imaging process issequential, and there is no assessment of the quality of thereconstructed image until after the measurement process is completed.Where a poor quality image is obtained, the measurements must berepeated, resulting in inconvenience to the patient and inefficiency inthe imaging process.

The volumetric scan is usually performed by orbiting detectors frommultiple directions in order to provide sufficient information toreconstruct a three-dimensional image of the radiation source by meansof computed tomography. The detectors are typically mounted on a gantryto provide structural support and to orbit the detector around theobject of interest. If the detector is a nuclear medicine detector, suchas scintillation detector or CZT detectors, for example Single photonemission computed tomography single photon emission computed tomography(SPECT) and positron emission tomography (PET) systems detector, acollimator that is used to restrict radiation acceptance, or thedirection of ray travel, is placed between it and the object beingimaged. Typically this collimator is constructed to provide amultiplicity of small holes in a dense, high-atomic-number material suchas lead or Tungsten. The rays will pass through the holes if they travelin a direction aligned with the hole but will tend to be absorbed by thecollimator material if they travel in a direction not aligned with theholes.

During the last years, a number Non-orbiting tomographic imaging systemshave been developed. For example U.S. Pat. No. 6,242,743, filed on Aug.11, 1998 describes tomographic imaging system which images ionizingradiation such as gamma rays or x rays and which: 1) can producetomographic images without requiring an orbiting motion of thedetector(s) or collimator(s) around the object of interest, 2) producessmaller tomographic systems with enhanced system mobility, and 3) iscapable of observing the object of interest from sufficiently manydirections to allow multiple time-sequenced tomographic images to beproduced. The system consists of a plurality of detector modules whichare distributed about or around the object of interest and which fullyor partially encircle it. The detector modules are positioned close tothe object of interest thereby improving spatial resolution and imagequality. The plurality of detectors view a portion of the patient orobject of interest simultaneously from a plurality of positions. Theseattributes are achieved by configuring small modular radiation detectorwith collimators in a combination of application-specific acquisitiongeometries and non-orbital detector module motion sequences composed oftilting, swiveling and translating motions, and combinations of suchmotions. Various kinds of module geometry and module or collimatormotion sequences are possible, and several combinations of such geometryand motion are shown. The geometric configurations may be fixed orvariable during the acquisition or between acquisition intervals.Clinical applications of various embodiments of the tomography inventioninclude imaging of the human heart, breast, brain or limbs, or smallanimals. Methods of using the non-orbiting tomographic imaging systemare also included.

Another example is described in United States Patent Application2010/0001200, published on Jul. 1, 2010, which describes an imagingsystem for radioimaging a region of interest (ROI) of a subject. Thesystem includes a housing, a support structure, which is movably coupledto the housing, and at least one motor assembly, coupled to the housingand the support structure, and configured to move the support structurewith respect to the housing. The system also includes at least twodetector assemblies, fixed to the support structure, and comprisingrespective radiation detectors and angular orientators. A control unitdrives the motor assembly to position the support structure in aplurality of positions with respect to the housing, and, while thesupport structure is positioned in each of the plurality of positions,drives the orientators to orient the respective detectors in a pluralityof rotational orientations with respect to the ROI, and to detectradiation from the ROI at the rotational orientations. Other embodimentsare also described.

SUMMARY OF THE INVENTION

According to some embodiments of the present invention there is provideda system of performing a volumetric scan. The system comprises a surfaceof positioning a patient in a space parallel thereto, a plurality ofextendable detector arms each the detector arm having a detection unithaving at least one radiation detector, and an actuator which moves thedetection unit along a linear path, and a gantry which supports theplurality of extendable detector arms around the surface so that eachthe linear path of each respective the extendable detector arm beingdirected toward the space.

Optionally, the system further comprises a controller for controllingeach the actuator to move a respective the detection unit along thelinear path according to a scanning pattern.

Optionally, the detection unit comprises a tilting mechanism for tiltingthe at least one radiation detector in a sweeping motion.

Optionally, the gantry is configured for radially disposing theplurality of extendable detector arms along an arch above the surface.

Optionally, the at least one radiation detector comprises at least onenuclear medicine (NM) detector.

Optionally, each the extendable detector arm comprises an X-rayradiation source and the at least one radiation detector being set tointercept a reflection of X-ray radiation emitted from the X-rayradiation source.

More optionally, the X-ray radiation source is part of the detectionunit. More optionally, the at least one radiation detector interceptsboth the reflection and Gamma ray radiation emitted from the body of thepatient.

More optionally, each the detection unit operates both in a photoncounting mode and in a flux measurement mode.

Optionally, the gantry rotates the plurality of extendable detector armsaround the body of the patient.

Optionally, the surface is at least one of a horizontal surface or avertical surface embedded with a plurality of additional radiationdetectors.

Optionally, the surface is at least one of a bed, a chair and a wall.

More optionally, at least one of the plurality of detection unitscomprises a proximity detector which estimates a distance between a tipof a respective the extendable detector arm and the body of the patient,the controller controls each respective the actuator according torespective the distance.

More optionally, at least one of the plurality of detection unitscomprises a pressure detector which estimates a pressure applied on thebody of the patient by a tip of a respective the extendable detectorarm, the controller controls each respective the actuator according torespective the pressure.

Optionally, at least one of the plurality of detection units comprisesan attenuation correction detector which captures additional radiationemitted from the body of the patient to correct a reconstruction of avolumetric image by radiation intercepted by respective the at least oneradiation detector.

More optionally, the attenuation correction detector is an ultrasonic(US) transducer.

More optionally, the system further comprises a breathing detector whichmonitors thoracic movements of the patient; the controller controls atleast one of the plurality of actuators according to the monitoring.

Optionally, the linear path extends from a plane defined by the gantry.

Optionally, the linear path is diagonal to the surface.

More optionally, the actuator rotates each the detection unit around anaxis parallel to a respective the linear path.

Optionally, the system further comprises at least one additional gantryeach supports a plurality of extendable detector arms around the surfacein a similar manner to the manner the gantry supports the plurality ofextendable detector arms.

More optionally, the tips of the plurality of extendable detector armsand the plurality of extendable detector arms are extended toward acommon axial plane of the body of the patient.

Optionally, the system further comprises at least one tilting motorwhich tilts at least one of the plurality of extendable detector arms inrelation to the gantry.

Optionally, each the detection unit comprises an array of a plurality ofradiation detectors, each set to move in sweeping motion.

According to some embodiments of the present invention there is provideda method of performing a volumetric scan that comprises a) providing asurface of positioning a patient in a space parallel thereto, b)linearly moving a plurality of detection units, each having at least oneradiation detector, from a plurality of distinct locations along aframework around the surface toward a plurality of points each at a lessthan a predefined distance from the body of the patient, c) interceptingradiation from the patient using each the at least one radiationdetector, and d) reconstructing a volumetric image of at least one partof the patient's body according to the radiation.

Optionally, the method further comprises radially disposing plurality ofdetection units to a plurality of new locations and repeating the c) andd) from the plurality of new locations.

Optionally, the plurality of points comprises a plurality of points ofcontact with the body of the patient.

Optionally, the plurality of points comprises a plurality of points ofproximity from the body, each the point of proximity being at a distanceof less than 5 cm from the body.

Optionally, the distinct locations are at least 5 cm from one another.

Optionally, the intercepting comprises tilting each the at least oneradiation detector in sweeping motion at the point of contact.

Optionally, the method further comprises selecting a group of theplurality of detection units according to a dimension of the body of thepatient, the linearly moving comprising linearly moving only members thegroup.

Optionally, the linearly moving comprises, for each the detection unit,detecting a distance from the body of the patient and linearly movingrespective the radiation detector according to the distance.

Optionally, the linearly moving comprises, using an actuator to move thedetection unit toward the body of the patient until a pressure appliedby the actuator is above a threshold.

Optionally, the linearly moving comprises monitoring breathing of thepatient and controlling the linear motion according to the monitoring.

Optionally, the system further comprises changing at least one ofemission and orientation of the plurality of detection units so as toincrease the resolution of the volumetric image in at least one regionof interest in relation to other regions of the volumetric image andrepeating the b)-d).

According to some embodiments of the present invention there is provideda system of performing a volumetric scan. The system comprises a surfaceof positioning a patient in a space parallel thereto, a plurality ofradiation detectors embedded in the surface and set to interceptradiation emitted from of at least one part of the patient's body, and areconstruction module which reconstructs a volumetric image of the atleast one part according to the intercepted radiation.

Optionally, the system further comprises of actuating unit for actuatingthe plurality of radiation detectors according to a scanning pattern.

Optionally, the system further comprises a gantry which supports aplurality of additional radiation detectors above the surface, theadditional radiation detectors are set to intercept additional radiationemitted from of the at least one part, the reconstruction modulereconstructs the volumetric image according to a combination of theintercepted radiation and the intercepted additional radiation.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

Implementation of the method and/or system of embodiments of theinvention can involve performing or completing selected tasks manually,automatically, or a combination thereof. Moreover, according to actualinstrumentation and equipment of embodiments of the method and/or systemof the invention, several selected tasks could be implemented byhardware, by software or by firmware or by a combination thereof usingan operating system.

For example, hardware for performing selected tasks according toembodiments of the invention could be implemented as a chip or acircuit. As software, selected tasks according to embodiments of theinvention could be implemented as a plurality of software instructionsbeing executed by a computer using any suitable operating system. In anexemplary embodiment of the invention, one or more tasks according toexemplary embodiments of method and/or system as described herein areperformed by a data processor, such as a computing platform forexecuting a plurality of instructions. Optionally, the data processorincludes a volatile memory for storing instructions and/or data and/or anon-volatile storage, for example, a magnetic hard-disk and/or removablemedia, for storing instructions and/or data. Optionally, a networkconnection is provided as well. A display and/or a user input devicesuch as a keyboard or mouse are optionally provided as well.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the invention are herein described, by way ofexample only, with reference to the accompanying drawings. With specificreference now to the drawings in detail, it is stressed that theparticulars shown are by way of example and for purposes of illustrativediscussion of embodiments of the invention. In this regard, thedescription taken with the drawings makes apparent to those skilled inthe art how embodiments of the invention may be practiced.

In the drawings:

FIG. 1 is a sectional schematic illustration of a volumetric scannerhaving a gantry radially supporting a plurality of extendable detectorarms, according to some embodiments of the present invention;

FIG. 2A is a sectional schematic illustration of the volumetric scannerwhere a disposition of one of the extendable detector arms along an archis depicted, according to some embodiments of the present invention;

FIGS. 2B-2D are sectional schematic illustrations of a plurality ofdetection units mounted on a circular gantry which may change theproximity of detection units from the body of a patient, according tosome embodiments of the present invention;

FIG. 3 is a lateral view of a portion of an extendable detector arm,such as depicted in FIG. 1, along an axis that is perpendicular to thelongitudinal axis of the patient bed 85, according to some embodimentsof the present invention;

FIG. 4 is a lateral schematic illustration of an exemplary gantry and apatient horizontally positioned on a patient bed, according to someembodiments of the present invention;

FIG. 5A is a sectional schematic illustration of an exemplary detectionunit in a tip of an extendable detector arm, according to someembodiments of the present invention;

FIG. 5B is a sectional schematic illustration of the exemplary detectionunit in the tip of an extendable detector arm of FIG. 5A a set ofrollers are mounted on the tip, according to some embodiments of thepresent invention;

FIG. 6A is a schematic illustration of an arrangement having a CTscanner and the volumetric scanner, according to some embodiments of thepresent invention;

FIG. 6B a sectional schematic illustration of a circular gantry,according to some embodiments of the present invention;

FIG. 7 is a sectional schematic illustration of an exemplary backsurface, along its latitudinal axis, below a pad on which a patientlies, according to some embodiments of the present invention;

FIG. 8 is a sectional schematic illustration of a volumetric scanner asdepicted in FIG. 1 with a patient bed as depicted in FIG. 7, accordingto some embodiments of the present invention;

FIG. 9 is a schematic illustration a volumetric scanner having aplurality of extendable detector arms each with a plurality of detectionunits, according to some embodiments of the present invention;

FIG. 10 is a schematic illustration of a volumetric scanner having aplurality of gantries, according to some embodiments of the presentinvention; and

FIG. 11 is a flowchart of a method of performing a volumetric scan,according to some embodiments of the present invention; and

FIG. 12 is another flowchart of a method of performing a volumetricscan, according to some embodiments of the present invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to methodand system of imaging and, more particularly, but not exclusively, tomethod and system of medical imaging.

According to some embodiments of the present invention there is provideda system of performing a volumetric scan of at least a part of a body ofa patient, such as a volumetric scanner, using a plurality of radiationdetectors which are moved toward the body of the patient. And arecapable of local translation or rotation, optionally separately.

The system includes a patient surface of positioning the patient in aspace parallel thereto. The patient surface may be adjusted to supportstanding patients, laying patients, seating patients, and/or leaningpatients. For example, the surface may be a horizontal alignmentsurface, such as a patient bed, a vertical alignment surface, such as awall or a back of a chair and the like.

The patient surface is optionally embedded with a plurality of radiationdetectors intercepts radiation emitted or reflected from the patient,for example as shown at FIG. 7. In other embodiments, the radiationdetectors are placed in the patient surface that is placed below or in apad on which a patient lies.

For brevity radiation emitted, transmitted through or reflected from thepatient may be referred to herein as radiation emitted from the patient.The system further includes a plurality of extendable detector arms.Each extendable detector arm has a detection unit with one or moreradiation detectors, such as nuclear medicine detectors, and an actuatorthat moves the detection unit along a linear path toward and from thebody of the patient. The system further includes a gantry, optionallyannular or semiannular, which supports the arms around the patient. Inuse, the patient may horizontally positioned on the surface, and theextendable detector arms may be used for bringing the detection units topoints in a predefined distance from the body of the patient and/or topoints of contact with the body of the patient. The projection ofradiation, such as gamma radiation, which is intercepted by thedetectors of the detection units allow reconstructing a volumetricimage. Optionally, each detection unit includes a radiation source, suchas an X-ray source that allows transmitting radiation into the body ofthe patient. In such embodiments, a volumetric image may bereconstructed according to both gamma and x-ray radiation which isemitted and reflected from the body of the patient. Optionally, theextendable detector arms and/or the gantry may be rotated tilted, and/ormoved along the patient surface according to a scanning pattern and/oruser instructions.

Optionally, the number of extendable detector arms which are used forreconstructing the volumetric image dependents on the dimension of thepatient. In such an embodiment, a limited number of extendable detectorarms may be used for imaging a thin patient and a larger number ofextendable detector arms may be used for imaging an obese patient.Optionally, a number of gantries with extendable detector arms are usedfor reconstructing a volumetric image of a patient. In such anembodiment, a single gantry may be used for imaging a thin patient and anumber of gantries may be used for imaging an obese patient.

According to some embodiments of the present invention, there isprovided a system of performing a volumetric scan. The system includes asurface of positioning a patient in a space parallel thereto, such as abed, and a plurality of radiation detectors which may be embedded intothe surface, which may be placed below a pad on which the patient lies,and set to intercept radiation emitted from of at least one part of thepatient's body, for example and as outlined above and described below.The system further includes a reconstruction module that reconstructs avolumetric image of the at least one part according to the interceptedradiation.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings and/or the Examples. The invention iscapable of other embodiments or of being practiced or carried out invarious ways.

Reference is now made to FIG. 1, which is a sectional schematicillustration of a system, such as a volumetric scanner 81, for example anuclear medicine (NM) scanner, having a gantry 80 radially supporting aplurality of extendable detector arms 83, optionally having their tipsdirected toward a common volumetric area above patient's bed 805,according to some embodiments of the present invention. Optionally, thevolumetric scanner 81 allows capturing a Clinically-Valuable Image ofthe patient, as defined below.

As used herein, an extendable detector arm means having a detector armhaving a varying length. The gantry 80 is optionally an annular and/orsemiannular frame that is designed to be placed around a surface 85 ofpositioning a patient for scanning in a space, such as a bed, referredto herein as a patient surface, for example as shown in FIG. 1. Eachextendable detector arm 83 may include a linear actuator 86 and adetection unit 84 that is connected to its tip for interceptingradiation from the scanned patient. For brevity, the term patient may beused to describe any body portion of a patient, for example one or moreorgans and/or a portion of an organ. The detection unit 84 includes oneor more radiation detectors, such as semiconductor radiation detectors,for example nuclear medicine (NM) detectors, for instance cadmium zinctelluride (CZT) detectors. The linear actuator 86 is designed tolinearly maneuver the detection unit 84 toward and from a location in aspace bounded or otherwise defined by gantry 80. Optionally, the linearactuator 86 is mechanical actuator that converts rotary motion of acontrol knob into linear displacement, a hydraulic actuator or hydrauliccylinder, for example a hollow cylinder having a piston, a piezoelectricactuator having a voltage dependent expandable unit, and/or anelectro-mechanical actuator that is based on an electric motor, such astep motor and the like. The linear actuators 86 of the extendabledetector arms 83 are connected to a controller 82 which converts digitalsignals of a scanning computing unit 82 into electronic signalsnecessary to control it. The control of each linear detector actuator 83is performed according to a volumetric scanning pattern calculatedand/or controlled by the scanning computing unit 82 and/or attenuationcorrection/scatter corrections (ACSCs), for example corrections ofbreathing motions, optionally calculated according to feedback from oneor more sensors, such as position sensors, which sense the actuallocation of the tip of the respective extendable detector arm 83. As theextendable detector arms includes only some of the total detection units84 which are used in the volumetric scanner 81, motion control whichrequire about 1 Kg moving force or less may be enabled. As such, they donot apply extensive force on the patient and may easily get in contactwith the patient's skin by using linear actuator 86, such as a pneumaticactuator.

When a patient 88 is positioned horizontally on the patient surface 85,the controller 82 instructs the linear actuators 86 to extend toward thepatient's body in a space above the patient surface 85, for examplealong the linear axes depicted in FIG. 1, such as numeral 90.Optionally, the instructions are provided according to a volumetricscanning pattern calculated and/or controlled by a scanning computingunit 87. Optionally, contrast materials, contrast agents and/or contrastmediums, are injected to the patient 88 before the scanning process. Thecontrast material may include any internally administered substance thathas, when imaged by the CT scanner, a different opacity from soft tissueon computed tomography, for example Barium, water, Iodine, and/orSterile saline.

Optionally, some or all of the extendable detector arms 83 have aproximity detector, for example as shown at 89, such as an electrostatictouch sensor, a capacitive, an infrared (IR) detector or an acousticproximity detector, such as an ultrasonic (US) transducer. The proximitydetector 89 is electrically connected to the controller 82 so as toallow the controller 82 to receive its feedback. The proximity detector89 indicates when the tip of the extendable detector arms 83 and/or thedetection unit 84 is in a certain distance from the body of the patient88. Optionally, the controller instructs the extending of the extendabledetector arms 83 until the proximity detector 89 feedback indicates thatthe tip of the extendable detector arms 83 is in touch with the body ofthe patient 88. Optionally, any group of extendable detector arms 83 maybe extended together, for example a group of 1, 2, 3, 4, 5, 6, 7, and 8extendable detector arms 83. Optionally, the proximity detector 89includes a pressure sensor which indicates when the tip of theextendable detector arm 83 applies a certain amount of pressure on thebody of the patient. In such a manner, the proximity detector 89 canindicate that the tip of the extendable detector arm 83 is held firmlyagainst the body of the patient. Optionally, the pressure applied byeach extendable detector arm 83 is no more than 1 kilogram (Kg).Optionally, the proximity detector 89 is placed about 1 centimeter (cm)from the tip of the extendable detector arm 83.

Optionally, some or all of the extendable detector arms 83 have abreathing detector, such as an US transducer which monitors thebreathing of the patient 88 for example by monitoring her thoracicmovements. In such an embodiment, the extending of the extendabledetector arms 83 may be coordinated with the breathing cycle of thepatient. Optionally, the same detector is used as a proximity detectorand as a breathing detector, for example a US transducer. Optionally,the same detector is also used as a pressure detector.

Optionally, as shown at FIG. 2A, each one of the extendable detectorarms 83 may be radially disposed 71 along an arch or a perimeter of acircle centered at a location above the patient surface 85. Optionally,any group of extendable detector arms 83 may be radially disposed 71together. The movement of the extendable detector arm 83 is optionallydefined by a path, such as a groove, in the gantry 80 and controlled bythe controller 82, for example according to a volumetric scanningpattern calculated and/or controlled by the scanning computing unit 82.Optionally, one or more motors actuate the movement of each extendabledetector arm 83 along the arch or perimeter according to the outputs ofthe controller 82.

Optionally, the gantry 80 may be rotated tilted, and/or moved along thepatient surface 85 according to the outputs of the controller 82 and/oruser instructions.

According to some embodiments of the present invention, the gantry 80 iscircular, for example as shown at FIG. 6B. Optionally, the volumetricscanner 81 allows capturing a Clinically-Valuable Image of the patient,as defined below. In such an embodiment, the gantry may be used torotate the extendable detector arms 83 around the patient 88.Optionally, the extendable detector arms 83 are rotated while being incontact with the body of the patient 88 and/or in proximity to the bodyof the patient 88.

Reference is now made to FIGS. 2B-2D, which are sectional schematicillustrations of a circular gantry 80 having a plurality of detectionunits 84, according to some embodiments of the present invention. Thoughthe detection units 84 are depicted as circular elements, they may havevarious forms and may be actuated as described above in relation toFIGS. 1 and 2. In FIG. 2B, the detection units 84 are located away fromthe body of the patient 88. FIG. 2C depicts the detection units 84 whenthey are located in a plurality of contact points with the body of thepatient 88 or in a plurality of proximity points from the body of thepatient 88.

In FIG. 2D, only some of the detection units 84 are located in aplurality of contact points with the head of the patient 88 or in aplurality of proximity points from the head of the patient 88. Asfurther described below, group of detection units 84 may be used toimage thin patients and/or organs with limited perimeters while othersare idle. In such a manner, the number of detection units 84 which areused in each scan is dynamic, allowing using the same scanner forscanning various organs and/or patients from a plurality of contactand/or proximity points with and/or from the patient 88. FIGS. 2B-2Dfurther depicts exemplary perimeters and radiuses of the volumetricscanner 81.

Reference is now also made to FIG. 3, which is a lateral view of anextendable detector arm, such as 83 in FIG. 1, along an axis that isperpendicular to the longitudinal axis of the patient surface 85,according to some embodiments of the present invention. Optionally, asshown at FIG. 2A, the extendable detector arm 83 moves along thelongitudinal axis of the patient surface 85, for example along the axisdepicted in 61, or swings so that the tip of the extendable detector arm83 scans the longitudinal axis of the patient surface 85, for exampleswings along a swing axis depicted in 62 or 63. Optionally, theextendable detector arm 83 is biased in an angle of about 2, 4, 5, 8,10, 15, 30 degrees or any intimidate or higher degree in relation to aplane traversing the supporting framework 80, for example along axis 95.

, and lateral translations of 1, 2, 5, 10 mm and/or greater, such as2-25 cm or more, for example, 3, 4, 5, 8, 12, and the like). Some ofthese details may be helpful in some claims as part of the futureprosecution process.

The movement of the extendable detector arm 83 is optionally defined bya path, such as a groove, in the gantry 80 and controlled by thecontroller 82, for example according to a volumetric scanning patterncalculated and/or controlled by the scanning computing unit 87.Optionally, one or more motors actuate the swing of the extendabledetector arm 83 and/or the movement thereof along the longitudinal axisof the patient surface 85 according to the outputs of the controller 82.

Optionally, some or all of the extendable detector arms 83 are rotatedaround their own axes, for example along the vector shown at 154.Optionally, the rotation is controlled by the controller 82, for exampleaccording to a volumetric scanning pattern calculated and/or controlledby the scanning computing unit 87.

Reference is now made to FIG. 4, which is a lateral schematicillustration of an exemplary gantry, such as 80, and a patient surface,such as 85, according to some embodiments of the present invention. FIG.4 depicts optionally motion vectors of the gantry 80. The gantry 80 maybe designed to move along these motion vectors during a scanningprocess, for example according to a volumetric scanning patterncalculated and/or controlled by the scanning computing unit 87.Optionally, one or more motors are connected to the gantry 80 tofacilitate the movement thereof along these vectors.

Optionally, the gantry 80 moves along the patient surface 85, forexample along the vector shown at 151. Optionally, the gantry 80 tiltedabout an axis perpendicular to the longitudinal axis of the patientsurface 85, for example along the vector shown at 152. Optionally, thegantry 80 rotates around a longitudinal axis of the patient surface 85,for example along the vector shown at 153. Optionally, the patientsurface 85 moves through the gantry 80.

Reference is now made to FIG. 5, which is a sectional schematicillustration of an exemplary detection unit 84 in a tip of an extendabledetector arm 83, according to some embodiments of the present invention.As shown at FIG. 5, the detection unit 84 includes a tilting mechanism401 for tilting one or more radiation detectors such as semiconductorradiation detectors 402. The tilting mechanism 401 optionally includes amount to which the radiation detectors 402 are connected. This tiltingmotion allows the semiconductor radiation detectors to scan a portion ofthe patient 88 in sweep motions, for example as described inInternational Application No. IL2005/001173, filed Nov. 19, 2005, whichis incorporated herein by reference. Optionally, the semiconductorradiation detectors 402 sweep among a number of positions. Optionally,the angular deviation between the different positions is about ¼, ⅓, ½and/or 1 degree. Optionally, the positions are spread over an angularopening of between about 10 and 120 degrees. Optionally, the angularopening and/or number of positions depend on the ROI, creating forexample 10, 20, 30, 50, 100, 200, 500 or any intermediate or smallernumber of positions for each radiation detector 402 which sweeps in ascan pattern. Optionally, the radiation detector 402 remains in eachangular position for a time period of about 0.1 second, 0.2 second, 0.5second, 0.8 second, 1 second, 1.5 second 3 sec, and 5 sec. Alternativelythe radiation detector 402 sweeps in a continuous motion.

Optionally, the tilting mechanism 401 includes a mount hinged on arotating shaft 405 and a motor for actuating the mount. The motor isoptionally controlled by the controller 82. For example, thesemiconductor radiation detectors 402 are 16×16 pixilated, 2.54×2.54 mmin size, CZT arrays. Optionally, the detector is fitted with acollimator, such as a parallel hole collimator 403. The collimator 403defines the solid angle from which radioactive emission events may bedetected. Optionally, different semiconductor radiation detectors 402have collimators with different characteristics. In such an embodimentcollimators of high and low resolutions may be combined. In such amanner, high and/or resolution images of the patient's body or anyportion thereof may be taken using the volumetric scanner 81.Optionally, the length of the collimation size of the collimators isbetween about 2 cm and about 3 cm and their width is between about 2 mmand about 3 mm.

As described above, the extendable detector arm 83 has a proximitydetector 89. Additionally or alternatively, the extendable detector arm83 may further include one or more attenuation correction transducers413, such as US transducers. Optionally, the ACSCs of each detectionunit 84 is performed based on the output of an adjacent attenuationcorrection transducer 413 in the extendable detector arm 83, for exampleas described in U.S. Pat. No. 7,652,259, filed on Apr. 11, 2003, whichis incorporated herein by reference. The ACSC allows correcting theeffect of bodily movements, for example breathing motion.

Optionally, a pad 406, such as a gel pad, for example an ultrasoniccoupling gel pad, is attached to the tip of the extendable detector arm83 and/or to the size of the extendable detector arm 83. The padprotects the patient's skin from being abraded by the extendabledetector arm 83 and optionally provides an ultrasonic coupling mediumfor the US transducers. Additionally or alternatively, as shown at FIG.5B, one or more rollers 407, such as wheels or balls, are attached tothe tip of the extendable detector arm 83. The rollers allow maintainingthe tip of the extendable detector arm 83 close to the skin of thepatient without rubbing so as to protect, or further protect, thepatient's skin from being abraded by the extendable detector arm 83. Theone or more rollers 407 also allow rotating the extendable detector arm83 along the contour of the body of the patient 88 while the tip of theextendable detector arm 83 is in contact with the body of the patient88.

According to some embodiments of the present invention, the volumetricscanner 87 includes a positioning unit which estimates the location ofthe patient before and/or during the scan. Optionally, the positioningunit includes one or more image sensors, such as one or more CCD camerasand an image processing module which estimates the contour of the bodyof the patient 88 according to an analysis of the output of the one ormore CCD cameras and instructs the extendable detector arm 83 to followa certain pattern according to the analysis. Optionally, the positioningunit includes one or more proximity sensors.

According to some embodiments of the present invention, some or all ofthe extendable detector arms 83 includes an X-ray source 408, such as acalibrated or uncalibrated solid radioactive source, an X-ray tube, forexample a commercially available tungsten tube, and an anode tube. Insuch an embodiment, the detection unit 84 may be used for capturing bothX-rays emitted from the X-ray source and Gamma ray from the body of thepatient, for example from radioactive tracer material, also known asradiopharmaceuticals. In such an embodiment, the acquired X-ray andGamma ray projections, optionally from detection units 84 in multipleextendable detector arm 83 are used to reconstruct an image, such as a3D image or a 4D Image, for example by applying known tomographicreconstruction algorithms. This image may then be manipulated to showthin slices along any chosen axis of the body, similar to those obtainedfrom other tomographic techniques, such as MRI, CT, and PET. Optionally,the X-rays and the Gamma ray are captured in different radiationinterception sessions. In a first group of radiation interceptionsessions Gamma-rays are captured and the X-ray source is idle. In asecond group of radiation interception sessions X-rays which are emittedfrom the X-ray source are captured. The time taken to obtain the X-rayand Gamma ray projection of in each angle and/or session may bevariable, for example 2 minutes per session. Optionally, the X-Ray fluxgenerated by the X-ray source is adapted to allow the detectors of thedetection units 84 to function both as SPECT detectors and CT detectors.In such embodiments the X-Ray flux allows the detectors to performphoton counting, for example at a rate of 80,000 counts per second.

By using X-ray source, the volumetric scanner 81 may be used forcomputerized tomography (CT). As the detection units 84 and the X-raysource 408 are placed in proximity to the body of the patient 88, theeffect of bodily movements has less affect on the reconstructed image.Moreover, the force applied by the plurality of extendable detector arms83 holds, or sustainably holds the body of the patient 88 in place andlimits its movement space. In such a manner, the patient moment has lesseffect on the reconstructed image. In such embodiments, the period ofeach scanning session, in which a slice is scanned, is set so that thetime spent for scanning each slice is roughly equivalent forreconstructing a CT and SPECT images. Optionally X-ray projections areused for attenuation and/or scatter corrections of Gamma ray projectionsand vice versa.

Optionally, the CT to SPECT information is used in real time (one affectthe scan of the other during the acquisition.

Optionally, the X-Ray source allows acquiring volumetric images by whenextremely low dose are used. These images may have low resolution andtherefore may be used for general anatomy/body contouring/motioncorrection, for example breathing correction, gating and the like.

Reference is now made to FIG. 6A, which is a schematic illustration ofan arrangement which includes a CT scanner 251, as known in the art, andthe volumetric scanner 81 which is placed abject thereto, for example asdepicted in FIG. 1, according to some embodiments of the presentinvention. In such an embodiment, the patient 88 may be simultaneouslyimaged using by the CT scanner 251 and the volumetric scanner 81.Optionally, the scanning period of the CT scanner 251 and the volumetricscanner 81 is similar, for example about 2 minutes.

Reference is now made to FIG. 7, which is a sectional schematicillustration of an exemplary back surface 185, along its latitudinalaxis, according to some embodiments of the present invention.Optionally, the back surface 185, which I optionally placed below a pad186 for lie on, allows capturing a Clinically-Valuable Image of thepatient, for example as defined below. The exemplary back surface 185includes a plurality of detection units 501. Optionally, each detectionunits as defined above, for example in relation to FIG. 5. Each one ofthe detection units 501 is connected to a controller and designed tocapture X-ray and/or Gamma ray projections. Optionally, the patientsurface 185 is the surface on which the patient lies. Optionally, asshown at FIG. 8, the back surface 185 is combined with the volumetricscanner 81 described in FIG. 1. In such an embodiment, the detectionunits 501 which are embedding in the back surface 185 are used tocapture projection from the back side of the patient 88, facilitating amore robust reconstruction of the patient body and/or the patient'sback. Optionally, in use, the bed is moved with the patient in and outof one or more gantries which support the aforementioned radiationdetectors. In such an embodiment, the back surface 185 may remain inplace while the bed moves.

Optionally, the detection units 501 are connected to one or more motorsthat allow changing their position in relation to the patient. In such amanner, the detection units 501 may be redistributed in the back surface185 or therebehind after the patient is positioned horizontally thereon.Optionally, the detection units 501 are connected controlled accordingto the outputs of the controller 82, for example according to avolumetric scanning pattern defined by the scanning computing unit 87.

Reference is now made to FIG. 9, which is a schematic illustration avolumetric scanner 81 having a plurality of extendable detector arms 683each with a plurality of detection units, for example as shown at 684,according to some embodiments of the present invention. In thisembodiment three extendable detector arms 683 are used for covering thepatient's body together with the exemplary back surface 185 depicted inFIG. 7, each from a different side. Optionally, only the frontextendable detector arm 683 has a plurality of detection units 684.Optionally, the volumetric scanner 81 allows capturing aClinically-Valuable Image of the patient, as defined below.

According to some embodiments of the present invention, the number ofextendable detector arms 83, which are used during a scan, is determinedaccording to the shape and/or dimension of the patient's body and/or theorgan which is about to be scanned, for example according to anestimation of the perimeter of patient at the axial plane which is aboutto be scanned. Optionally, the estimation is made using image processingtechniques, for example by analyzing an image of the patient captured byan image detector and/or according to the outputs of some or all of theproximity detectors. For example, four extendable detector arms 83 maybe used for imaging a body of a child, a thin patient, and/or a limb ofthe patient, and six extendable detector arms 83 may be used for imaginga body of an obese patient. In another example, four extendable detectorarms 83 may be used for imaging the brain of a patient, creating acerebral volumetric image, for example as shown in FIG. 2D, and sixextendable detector arms 83 may be used for imaging the thorax of thepatient.

According to some embodiments of the present invention, the radiationdetectors of the detection unit 84 are set work both in a photoncounting mode and in a flux measurement mode. Optionally, the detectionunit 84 changes its working mode intermediately or sequentially. Forexample, one or more of the detection units 84 may be set tointermittently intercept Gamma radiation emitted from Tc99m at betweenabout 130 Kilo electronvolt (KeV) and about 150 KeV and X-ray radiationfrom the body of the patient 88 at about 200 KeV. In such a manner, anenergy window of between about 150 KeV and about 250 KeV may be used fordetecting X-ray photons and separated them from Gamma ray photons. Assuch photons include relatively low scattering, the quality of the X-raybased image is relatively high. Optionally, the modes change everysecond such that in one second X-ray is intercepted and evaluated and inthe following Gamma-ray is intercepted and evaluated. Optionally, anumber of X-ray transmissions are performed in each X-ray session,optionally one every 0.1 second.

Optionally, the radiation detectors are optimized to measure the totalflux of photons rather than being optimized for short acquisition withhigh flux of photons where each photon is characterized. In suchembodiments, scatter affects the image. Optionally, the overall NMacquisition time is reduced to a scale of between about 1 minute andabout 2 minutes for a certain region or less. In such a manner, theaccuracy of the image registration may be increased, the number of useddetectors may be reduced. By selecting an energy window, as describedabove, and checking it for each photon, photons may be filtered withhigh probability of being scattered from a lateral origin.

It should be noted that when the intercepted radiation is X-rayradiation, the X-ray source may be as depicted in numeral 408 of FIG. 5and/or from an X-ray source placed in the gantry, for example as shownin FIG. 6B. The detection units may be activated in any of theaforementioned modes, separately and/or jointly, in any stage.

According to some embodiments of the present invention, a numberscanning sessions are performed by the extendable detector arms 83. Insuch an embodiment, a group of extendable detector arms 83 is used toimage the body of the patient 88 in a number of consecutive sessions. Ineach consecutive session other portions of the patient's body arescanned. In such an embodiment, patients in various sizes may be scannedusing a limited number of extendable detector arms 83. For example, fourextendable detector arms 83 may be used for imaging a body of a child, athin patient, and/or a limb of the patient in a single session and abody of an obese patient in two or three sessions. Though this processmay increase the time it takes to scan an obese patient, it allows usinga device with less extendable detector arms 83.

According to some embodiments of the present invention, the back surface185, or any other surface on which the patient is placed, is set to bevertically actuated, brings the patient's body closer to the detectionunits 84, for example to the tips of the extendable detector arms 83.

Reference is now also made to FIG. 10, which is a schematic illustrationof a volumetric scanner 81 having a plurality of gantries 800, eachoptionally defined as gantry 80 of FIG. 1, according to some embodimentsof the present invention. Optionally, the number of used gantries 800 isdetermined according the shape and/or dimension of the patient's body,for example according to an estimation of the perimeter of patient. Forexample, a single gantry 800 is used for imaging a body of a child, athin patient, and/or a limb of the patient, and two or more gantries 800may be used for imaging a body of an obese patient. Optionally, thegantries 800 are used for imaging parallel portions of the patient'sbody 88. Optionally, the extendable detector arms 83 of differentgantries 800 are tilted to image a common portion of the patient's body88. In such an embodiment the tip of the extendable detector arms 83 mayintertwine along a common plane when they are extended to by in touchwith the patient's body. For example, extendable detector arms 83 of afirst gantry may be from two sides of an extendable detector arm of asecond gantry. Optionally, each one of the gantries 800 is synchronizedwith one or more detection units 501 which are embedded in the patientsurface, for example mounted in a surface below a mattress of a patientbed, for example as shown in FIG. 7.

The extendable detector arms 83 allow directing the detection units 84to face different areas of the patient surface. Rather than facing thegeometrical center of a space that is bounded by the gantry 80, thedetection units 84 may be directed to face a selected region of interestwhich is outside of the bounded space.

Reference is now also made to FIG. 11, which is a flowchart of a methodof performing a volumetric scan 200, according to some embodiments ofthe present invention. Optionally, the volumetric scan allows capturinga Clinically-Valuable Image of the patient, as defined below. First, asshown at 201 a surface of positioning a patient in a space parallelthereto is provided, for example the patient surface 85. In use, thepatient lies down on the patient surface 85. Then, as shown at 202, aplurality of radiation detectors, such as the detectors in the detectionunits 84, are linearly extended toward a plurality of points of contacton the body of the patient and/or a plurality of points of proximity inrelation to the body of the patient, for example by the extending of thelinear actuators 86 from a plurality of distinct locations around thesurface 85, on a framework, such as the gantry 80. Optionally, a pointof proximity is defined a location from which the distance to the bodyof the patient is less than 5 cm, for example 1 cm, optionally 0.

Optionally, these distinct locations are apart from one another, forexample 5 centimeter (cm) apart from one another, 10 cm apart from oneanother, 15 cm apart from one another or any intermediate or greaterdistance. Optionally, the extending length and/or angle of theextendable detector arms 83 is set according to a volumetric scanningpattern, for example controlled according to the controller 92 asdefined above. Now, as shown at 203, radiation from the patient isintercepted by the plurality of radiation detectors. The radiation maybe gamma ray and/or X-ray radiation, for example as outlined above. Thisallows, as shown at 204 reconstructing a volumetric image of one or moreparts of the patient's body, for example using known SPECT, PET and/orCT imaging reconstruction techniques, for example as described inInternational Application No. IL2005/001173, filed Nov. 19, 2005, whichis incorporated herein by reference.

FIG. 12 is another flowchart of a method of performing a volumetricscan, according to some embodiments of the present. Blocks 201-204 areas depicted in FIG. 11, however FIG. 12 further depicts blocks 210 and211 in which the detection units 84 are optionally pulled from thepoints of contact and/or points of proximity and rotated to allowrepeating 202-203 from other points of contact and/or points ofproximity. The rotation may be performed by rotating the gantry 80 onwhich the detection units 84 are mounted. Optionally, the volumetricscan allows capturing a Clinically-Valuable Image of the patient, asdefined below.

Optionally, as shown at 212, a region of interest is calculated, orrecalculated, according to data in the image reconstructed in 211. Insuch an embodiment, the orientation of the extendable detector arms 83and/or emission of the X-ray source 408 of some or all of them may bechanged according to data in the image reconstructed in 211, for examplea characteristic of pathological pattern. The orientation and/oremission of the detectors may be adjusted according to the new region ofinterest, for example to optimize the scan thereof. This process may beiteratively repeated, concentrating the imaging effort in the changingregion of interest.

Optionally, the volumetric scanning pattern is adapted according to datathat is captured and analyzed during the scan. In such an embodiment,suspected pathological sites may be detected by analyzing images whichare substantially constantly reconstructed during the scan. Theseimages, which are reconstructed based on a limited scanning data, allowcapturing an image of a region of interest, which optionally includes asuspected pathological site that is indicative of abnormal cellularcomposition, cellular growth, fractures, lesions, tumors, hematomas andthe like.

Additionally or alternatively, the scanning is adapted to focus on apredefined region of interest. Optionally, predefined region of interestis defined automatically and/or manually according to medicalinformation that is received about the patient, for example similarly tothe described in International Patent Application Publication No.WO2008/075362 published on Jan. 26, 2008, which is incorporated hereinby reference. As used herein, medical information means, inter alia,information which is related to the patient, such as laboratory results,therapeutic procedure records, clinical evaluations, age, gender,medical condition, ID, genetic information, patient medical record, dataindicating of metabolism, blood pressure, patient history,sensitivities, allergies, different population records, treatmentmethods and the outcome thereof, epidemiologic classification, andpatient history, such as treatment history. In such embodiments, theorientation of the directable detectors may be changed in a manner thatthey are facing toward a region of interest of the patient, for examplea known location of a tumor and/or a fracture. The coordinates of thelocation may be gathered by analyzing the medical information, forexample using image processing techniques and/or manually inputted bythe system operator and/or caretaker.

Additionally or alternatively, the intensity of the radiation that isemitted by the X-ray source 408 may be changed for example reducedand/or intensified during the volumetric scan. In such a manner, theradiation dose per volumetric scan may be reduced. The emission changereduces the total amount of the radiation that is absorbed by thepatient and/or allows avoiding some or all of the redundant emissions.For example, instead of creating a high resolution volumetric CT imageof the torso by irradiating the patient, from a plurality of angles,with fluxes which are high enough to overcome all the possibleobstacles, for example ribs, initial scanning sessions and/or receivedmedical information are used for identifying these obstacles so as toreduce the emission in areas in which they are present. Then, sidewayviews, optionally unradial, are taken to complete the missing data. Insuch a manner, data from a low-flux beam that would go radially towardsthe obstacle is compensated by either temporarily increasing the flux inan unblocked area and/or by taking additional side views that passtoward the region of interest.

According to some embodiments of the present invention, the orientationof the extendable detector arms 83 and/or emission of the X-ray source408 of some or all of them may be changed according to characteristicsof the region of interest and/or the location thereof. Thecharacteristics can affect area to be scanned, for example the scanningspeed, the contrast martial flux and/or wait time, the estimatedscatter, attenuation, and/or resolution and the like. All these may beautomated for that purpose, save time, and improve quality. Theorientation and/or emission of the detectors may be adjusted accordingto characteristics of a suspected abnormality and thus optimizing theactual scan of the region of interest. For example, a change in anestimated anatomy, physiology, and/or metabolism may be detected duringthe performance of the scan and taken into account. The orientationand/or emission of the detectors may be changed to acquire more datapertaining to the region of interest and/or the specific suspectedpathological sites.

According to some embodiments of the present invention, the orientationof the extendable detector arms 83 and/or emission of the X-ray source408 of some or all of them may be changed so as to reduce the radiationthat is transmitted via and/or toward radiation sensitive areas, such asthe gonads, the eyes, the spinal cord, the salivary glands and/orbreasts. In such an embodiment, the radiation sensitive areas aredetected either in advance or in the initial scanning sessions. Then,the detectors are directed to avoid transmitting radiation toward theradiation sensitive areas and/or to reduce the intensity of the emissiontransmitted toward the radiation sensitive areas.

In such an embodiment, the detection units 84, and their radiation, areprimarily focused on the region of interest. In such a manner, thefocusing on one or more regions of interest may continuously improved,allowing focusing the resources on an area that matters the most for thediagnosis of the medical condition of the patient.

Definition of a Clinically-Valuable Image

In consequence to the features described above, the volumetric scanner81 is capable of producing a “clinically-valuable image” of anintra-body region of interest (ROI) containing a radiopharmaceutical,while fulfilling one or more of the following criteria:

1. the volumetric scanner 81 is capable of acquiring at least one of5000 photons emitted from the ROI during the image acquisitionprocedure, such as at least one of 4000, 3000, 2500, 2000, 1500, 1200,1000, 800, 600, 400, 200, 100, or 50 photons emitted from the ROI. Inone particular embodiment, the volumetric scanner 81 is capable ofacquiring at least one of 2000 photons emitted from the ROI during theimage acquisition procedure;2. the volumetric scanner 81 is capable of acquiring at least 200,000photons, such as at least 500,000, 1,000,000, 2,000,000, 3,000,000,4,000,000, 5,000,000, 8,000,000, or 10,000,000 photons, emitted from aportion of the ROI having a volume of no more than 500 cc, such as avolume of no more than 500 cc, 400 cc, 300 cc, 200 cc, 150 cc, lOOcc, or50 cc. In one particular embodiment, the volumetric scanner 81 iscapable of acquiring at least 1,000,000 photons emitted from a volume ofthe ROI having a volume of no more than 200 cc;3. the volumetric scanner 81 is capable of acquiring an image of aresolution of at least 7×7×7 mm, such as at least 6×6×6 mm, 5×5×5 mm,4×4×4 mm, 4×3×3 mm, or 3×3×3 mm, in at least 50% of the reconstructedvolume, wherein the radiopharmaceutical as distributed within the ROIhas a range of emission-intensities I (which is measured as emittedphotons/unit time/volume), and wherein at least 50% of the voxels of thereconstructed three-dimensional emission-intensity image of the ROI haveinaccuracies of less than 30% of range I, such as less than 25%, 20%,15%, 10%, 5%, 2%, 1%, or 0.5% of range I. For example, theradiopharmaceutical may emit over a range from 0 photons/second/cc to10A5 photons/second/cc, such that the range I is 105 photons/second/cc,and at least 50% of the voxels of the reconstructed three-dimensionalintensity image of the ROI have inaccuracies of less than 15% of rangeI, i.e., less than 1.5×104 photons/second/cc. For some applications, thestudy produce a parametric image related to a physiological processoccurring in each voxel. In one particular embodiment, the image has aresolution of at least 5×5×5 mm, and at least 50% of the voxels haveinaccuracies of less than 15% of range I;4. the volumetric scanner 81 is capable of acquiring an image, which hasa resolution of at least 7×7×7 mm, such as at least 6×6×6 mm, 5×5×5 mm,4×4×4 mm, 4×3×3 mm, or 3×3×3 mm, in at least 50% of the reconstructedvolume, wherein the radiopharmaceutical as distributed within the ROIhas a range of emission-intensities I (which is measured as emittedphotons/unit time/volume), and wherein at least 50% of the voxels of thereconstructed three-dimensional emission-intensity image of the ROI haveinaccuracies of less than 30% of range I, such as less than 25%, 20%,15%, 10%, 5%, 2%, 1%, or 0.5% of range I. For example, theradiopharmaceutical may emit over a range from 0 photons/second/cc to105 photons/second/cc, such that the range I is 105 photons/second/cc,and at least 50% of the voxels of the reconstructed three-dimensionalintensity image of the ROI have inaccuracies of less than 15% of rangeI, i.e., less than 1.5×10 photons/second/cc. For some applications, thestudy produces a parametric image related to a physiological processoccurring in each voxel. In one particular embodiment, the image has aresolution of at least 5×5×5 mm, and at least 50% of the voxels haveinaccuracies of less than 15% of range I;5. the volumetric scanner 81 is capable of acquiring an image, which hasa resolution of at least 20×20×20 mm, such as at least 15×15×15 mm,10×10×10 mm, 7×7×7 mm, 5×5×5 mm, 4×4×4 mm, 4×3×3 mm, or 3×3×3 mm,wherein values of parameters of a physiological process modeled by aparametric representation have a range of physiological parameter valuesI, and wherein at least 50% of the voxels of the reconstructedparametric three-dimensional image have inaccuracies less than 100% ofrange I5 such as less than 70%, 50%, 40%, 30%, 25%, 20%, 15%, 10%, 5%,2%, 1%, or 0.5% of range I. For example, the physiological process mayinclude blood flow, the values of the parameters of the physiologicalprocess may have a range from 0 to 100 cc/minute, such that the range Iis 100 cc/minute, and at least 50% of the voxels of the reconstructedparametric three-dimensional image have inaccuracies less than 25% ofrange I, i.e., less than 25 cc/minute. In one particular embodiment, theimage has a resolution of at least 5×5×5 mm, and at least 50% of thevoxels have inaccuracies of less than 25% of range I; and/or6. the volumetric scanner 81 is capable of acquiring an image, which hasa resolution of at least 7×7×7 mm, such as at least 6×6×6 mm, 5×5×5 mm,4×4×4 mm, 4×3×3 mm, or 3×3×3 mm, in at least 50% of the reconstructedvolume, wherein if the radiopharmaceutical is” distributed substantiallyuniformly within a portion of the ROI with an emission-intensity I+/−10%(which is defined as emitted photons/unit time/volume), and wherein atleast 85% of the voxels of the reconstructed three-dimensionalemission-intensity image of the portion of the ROI have inaccuracies ofless than 30% of intensity I, such as less than 15%, 10%, 5%, 2%, 1%,0.5%, 20%, or 25% of intensity I. For example, the radiopharmaceuticalmay be distributed within a volume with a uniform emission-intensity Iof 10Λ5 photons/second/cc, and at least 85% of the voxels of thereconstructed three-dimensional intensity image of the volume haveinaccuracies of less than 15% of intensity I, i.e., less than 1.5×104photons/second/cc. For some applications, the same definition may applyto a study which produces a parametric image related to a physiologicalprocess occurring in each voxel. In one particular embodiment, the imagehas a resolution of at least 5×5×5 mm, and at least 50% of the voxelshave inaccuracies of less than 15% of intensity I.

It is expected that during the life of a patent maturing from thisapplication many relevant systems and methods will be developed and thescope of the term image, scanning, and directable detector is intendedto include all such new technologies a priori.

As used herein the term “about” refers to ±10%.

The terms “comprises”, “comprising”, “includes”, “including”, “having”and their conjugates mean “including but not limited to”. This termencompasses the terms “consisting of” and “consisting essentially of”.

The phrase “consisting essentially of” means that the composition ormethod may include additional ingredients and/or steps, but only if theadditional ingredients and/or steps do not materially alter the basicand novel characteristics of the claimed composition or method.

As used herein, the singular form “a”, “an” and “the” include pluralreferences unless the context clearly dictates otherwise. For example,the term “a compound” or “at least one compound” may include a pluralityof compounds, including mixtures thereof.

The word “exemplary” is used herein to mean “serving as an example,instance or illustration”. Any embodiment described as “exemplary” isnot necessarily to be construed as preferred or advantageous over otherembodiments and/or to exclude the incorporation of features from otherembodiments.

The word “optionally” is used herein to mean “is provided in someembodiments and not provided in other embodiments”. Any particularembodiment of the invention may include a plurality of “optional”features unless such features conflict.

Throughout this application, various embodiments of this invention maybe presented in a range format. It should be understood that thedescription in range format is merely for convenience and brevity andshould not be construed as an inflexible limitation on the scope of theinvention. Accordingly, the description of a range should be consideredto have specifically disclosed all the possible subranges as well asindividual numerical values within that range. For example, descriptionof a range such as from 1 to 6 should be considered to have specificallydisclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numberswithin that range, for example, 1, 2, 3, 4, 5, and 6. This appliesregardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to includeany cited numeral (fractional or integral) within the indicated range.The phrases “ranging/ranges between” a first indicate number and asecond indicate number and “ranging/ranges from” a first indicate number“to” a second indicate number are used herein interchangeably and aremeant to include the first and second indicated numbers and all thefractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, forclarity, described in the context of separate embodiments, may also beprovided in combination in a single embodiment. Conversely, variousfeatures of the invention, which are, for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable subcombination or as suitable in any other describedembodiment of the invention. Certain features described in the contextof various embodiments are not to be considered essential features ofthose embodiments, unless the embodiment is inoperative without thoseelements.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the present invention. To the extent thatsection headings are used, they should not be construed as necessarilylimiting.

What is claim is:
 1. A radiation detection apparatus for detectingradiation emanating from a body, comprising a detector arm whichcomprises: a) a radiation detector; b) a collimator; and c) a contactbase positioned so as to be between said collimator and said body whensaid apparatus is used to detect radiation from said body, said contactbase being sufficiently distant from said collimator to enable at leastpart of said collimator to move to change direction of aim with respectto said body while said contact base is in stable contact with a surfaceof said body.
 2. The apparatus of claim 1, wherein said collimator isswivel-mounted.
 3. The apparatus of claim 1, wherein said contact basecomprises a pad which comprises a gel that transmits ultrasoundvibrations.
 4. The apparatus of claim 1, wherein said contact basecomprises a roller which rolls along said body surface when said contactbase is in contact with said body surface while a distal portion of saidarm is moved along said body surface.
 5. The apparatus of claim 1,further comprising a plurality of detector arms.
 6. The apparatus ofclaim 1, further comprising a gantry connecting to a proximal portion ofsaid detector arm and a mechanical actuator operable to move a distalportion of said arm along said body surface.
 7. The detector arm ofclaim 6, wherein said actuator is operable to rotate said detector whilesaid contact base is in contact with said body surface.
 8. A method ofdetecting radiation emanating from a body, comprising: a) using anautomated arm positioning system to position a distal portion of adetector arm so that said distal portion is in contact with a surface ofsaid body and so that a radiation detector comprised in said distalportion is held at a distance from said body surface; and b) using saidautomated arm positioning system to move said distal portion of said armalong said body surface while using said radiation detector to detectradiation from said body.
 9. The method of claim 8, further comprisingusing an image processing module to estimate a contour of said bodybased on images from one or more image sensors, and controlling saidmovement of said arm to follow a pattern determined according to saidestimated body contour.
 10. The method of claim 8, further comprisingusing said automated arm positioning system to position and move aplurality of detector arms.
 11. The method of claim 8, wherein saiddistal portion of a detector arm comprises at least one roller, and saidmoving of said arm comprises rolling a distal portion of said arm alongsaid body surface.
 12. The method of claim 8, wherein said radiationdetector comprises a collimator mounted on a swivel, the method furthercomprising swiveling said collimator while said distal portion is incontact with said body surface, and using said swiveled collimator todetect radiation from a plurality of directions.
 13. The method of claim8, wherein said distal portion of said detector arm comprises aplurality of individually aimable radiation detectors.
 14. The method ofclaim 13, wherein at least some of said plurality radiation detectorsunits are independently displaceable within said distal portion of saiddetector arm.
 15. The method of claim 13, further comprising aiming saidplurality of detector units so as to each detect radiation from a samebody region.
 16. The method of claim 8, wherein said detector arm issupported by a gantry.
 17. The method of claim 16, further comprisingmoving said distal portion of said detector arm by at least one of: a)rotating said gantry; b) tilting said gantry; and c) moving said gantryalong said body surface.
 18. The method of claim 8, further comprisingrotating said detector arm while said detector arm is in contact withsaid body surface.
 19. A method of volumetric scanning which comprisesscanning a part of a patient's body using a detector arm which comprisesa plurality of radiation detectors each mounted with a collimator whichdefines the solid angle from which radioactive emission events may bedetected by its associated detector, comprising alternating betweenlow-resolution and high-resolution scanning by alternating between useof at least one detector associated with a relatively low resolutioncollimator and use of at least one detector associated with a relativelyhigh resolution collimator.
 20. The method of claim 19, furthercomprising utilizing information gleaned during said use of saidrelatively low resolution collimator to calculate an aiming position forsaid relatively high resolution collimator.
 21. The method of claim 20,further comprising moving said relatively high resolution collimatorwithin said detector arm to said calculated aiming position.
 22. Amethod of volumetric scanning which comprises: a) scanning a part of apatient's body using a detector arm which comprises a radiation detectorand an x-ray source; b) using said radiation detector to detect gammaradiation; and c) using said radiation detector to detect reflectedx-ray radiation originating from said x-ray source.
 23. The method ofclaim 22, further comprising using x-ray data collected from saidradiation detector in calculations of displayable images of detectedgamma-ray data.
 24. The method of claim 22, further comprising usinggamma ray data collected from said radiation detector in calculations ofdisplayable images of detected x-ray data.